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BIOLOGY IN SOUTH INDIA, FALL 2015, A6-A11
BIOLOGY IN SOUTH INDIA is a publication of St. Olaf College www.stolaf.edu
ARTICLE
Mercury Pollution in Kodaikanal Caused by a Thermometer Factory Spill in 2001
Hunter O. Lin
Biology Department, St. Olaf College, Northfield, MN 55057
Mercury exposure poses itself as a significant health
concern to the people of Kodaikanal, India. In 2001, the
town of Kodaikanal suffered mercury contamination due to
the improper storage and disposal of mercury by a local
thermometer factory. Kodai Lake and Gymkhana
Marshland are situated within a one-mile radius from the
thermometer factory. Our present study determined total
mercury concentration in water samples from Kodai Lake
and Gymkhana Marshland. Total mercury (HgT) of 0.17 -
0.54 µg l-1 was seen in Kodai Lake waters while Gymkhana
Marshland showed values of 0.16 - 1.20 µg l-1. The results
show that the mercury pollution in Kodai Lake is slightly
lower than values reported in 2006. In addition, higher HgT
concentrations found in the marshland inlet and lower HgT
concentrations found in the marshland outlet suggests that
Gymkhana Marshland may play a role in the filtration of
contaminants in surface water before entering the lake.
Key words: mercury pollution; ICP-MS, lake water,
sediment; mercury poisoning
1.0. INTRODUCTION
For decades, fear of mercury exposure has been
slowly increasing globally. Exaggerated reports about
mercury exposure have long circulated the media, slowly
increasing public concern about exposure to this metal.
According to Baum (2012), the concerns of public health
agencies about the health effects of elemental (or metallic)
mercury exposure in children have also been increasing.
Furthermore, Clarkson (1993) explains that the increasing
concentrations of mercury in our environment, through the
improper use and disposal of elemental mercury, is a major
environmental issue. Exposure to this heavy metal
becomes a critical health issue, due to its ability to bio-
accumulate in different organs and tissues, and later cause
cytotoxicity.
1.1. HISTORY OF KODAI LAKE
Kodaikanal is referred to as the “Princess of Hill
Stations.” This tourist town with a population of 36,501
(Census Organization of India 2011) is located in Tamil
Nadu’s Dindigul district and sits at an elevation of 2,133
meters above sea level. Kodaikanal’s average annual
rainfall of 165-cm and temperatures of 67 ºF (high) and 52
ºF (low) during summer and 63 ºF (high) and 47 ºF during
winter makes for a perfect tourist destination (World
Meteorological Organization 2016).
Kodaikanal Lake, also referred by the locals, as “Kodai
Lake” is a man-made star-shaped lake located in the heart
of Kodaikanal, Tamil Nadu. The 0.24 km2 lake was built by
Sir Vere Hendry Levinge, the Collector of Madurai, in 1863
by damming three streams previously flowing through the
town (Lockwood 2003). Following the public extension of
services offered by the Kodaikanal Boat & Rowing Club in
1932, Kodaikanal became the most popular hill station
within South India (Kodai.com 2016). During the weekends
Kodaikanal’s pleasant climate and attractions such as
Coaker’s Walk, Kodai Lake, Bryant Park, and the local
shops are crowded with tourists coming from all over India.
1.2. THERMOMETER FACTORY SPILL IN 2001
Hindustan Unilever once operated a thermometer
factory in Kodaikanal, India that produced some 100,000-
150,000 thermometers per month. In 2001 the
thermometer factory was responsible for a 7-ton mercury
spill, as the result of the company’s improper storage and
disposal of mercury (Justice Bhargava 2003). The factory
was located approximately uphill less than one kilometer
from Kodai Lake (Fig. 1). After operating for 18 years,
Hindustan Unilever’s thermometer factory closed its doors
in 2001 (Greenpeace 2001).
Fourteen years later, Hindustan Unilever’s improper
usage and disposal of elemental mercury remains a crisis
to the environmental health of Kodaikanal’s Shola hollowed
forests. Pippa Mukherjee, an NGO administrator at Palni
Hills Conservation Council, raises her concern about the
presence of mercury in the Kodai Lake waters, which is
consumed in many areas inside and outside of Kodaikanal
(Personal Communication, October 2015). Pippa
Mukherjee adds that awareness about the mercury
pollution is lacking in Kodaikanal and although concerns
are slowly being revived by local organizations, such as
PHCC, the mercury pollution is a critical public health
matter that needs to be addressed.
1.3. HEALTH EFFECTS OF MERCURY
Mercury is a non-essential and toxic metal to the
human body (Agency for Toxic Substances and Disease
Registry 1999, U.S. Environmental Protection Agency
2000, Karunasagar et al. 2006, Park and Zheng 2012, Li et
al. 2015b). This metal exists in three forms: organic,
inorganic, and elemental (or metallic, Hg0). Mercury’s
omnipresence and unique physical properties has allowed
for anthropogenic uses, such as in scientific
instrumentations (thermometers, barometers, etc.,) and
daily household products such as fluorescent light bulbs
(Gochfeld 2003).
Lin, H.O. Mercury Pollution A7
Figure 1. Water sampling points 1-5 in Kodai Lake and points 6-10 in Gymkhana Marshland. Sampling conditions and parameters are
summarized in Table 1. Original map modified and reproduced from Karunasagar et al. (2006). Hindustan Unilever Ltd. Thermometer
Factory original location marked by the yellow star, and is up a hill from Kodai Lake and just across a single road (Lower Shola Road).
Mercury is mainly produced from by the Amalden mine
in Spain. Other production sites for mercury are located in
Yugoslavia and in the United States, more specifically in
California (PhysLink.com 2016). Mercury is considered
inorganic when it is bound to another chemical to form a
salt compound. Inorganic mercury (also sometimes
referred to as ionic or oxidized mercury) can exist in two
oxidative states: Mercurous mercury (Hg1+) and mercuric
mercury (Hg2+). On the other hand, mercury is considered
organic when anaerobic microorganisms in the
environment methylate mercury in its elemental or
inorganic form by attaching a methyl group to the mercury
ion to form methylmercury (CH3Hg+) (Agency for Toxic
Substances and Disease Registry 1999).
Elemental (or metallic) mercury (Hg0) is formed when
the naturally occurring form of mercury, namely mercuric
sulfide or cinnabar ore (HgS), is heated, and thus reducing
the oxidation state of the mercury ion from Hg2+ to Hg0. In
addition, elemental mercury is considered the only
common metal to have a liquid state at room temperature.
However, due its high vapor pressure elemental
mercury can be easily released into the atmosphere (Baum
2012). Although there are many forms of mercury naturally
existing in the environment, elemental mercury is the most
common form (Agency for Toxic Substances and Disease
Registry 1999).
According to the U.S. Environmental Protection
Agency (2000), the detrimental health effects of mercury
exposure are most commonly seen when vapors of
mercury are inhaled and absorbed through the lungs. EPA
adds that when elemental mercury is spilled or products
containing elemental mercury breaks, mercury vapors are
easily released to the air especially in a warm or poor-
ventilated area. It is important to note that the magnitude
and duration of exposure, exposure routes, and the form of
the mercury compound may explain the severity of toxicity
that results from mercury exposure (Agency for Toxic
Substances and Disease Registry 1999).
A review by Park and Zheng (2012) on health
implications of mercury exposure explains that acute
exposure to mercury vapors through inhalation can lead to
BIOLOGY IN SOUTH INDIA, FALL 2015, A6-A11 A8
severe lung damage or death due to hypoxia.
Approximately 70-80% of mercury vapor inhaled is retained
and absorbed to the bloodstream. In addition, since the
biological half-life of elemental mercury is approximately 60
days, elemental mercury can stay in the body for weeks or
months. Although most of the elemental mercury in the
bloodstream will accumulate in the kidneys, some may
accumulate in the brain and cause toxic neurologic effects
(Agency for Toxic Substances and Disease Registry 1999).
It is important to note that once elemental mercury
accumulates in organ tissue, elemental mercury can
undergo biotransformation to the toxic form Hg2+ and
retained in the body in periods of several weeks or months
(Baum 2012). Most elemental and inorganic form of
mercury absorbed and trapped in organ tissues in the body
eventually leaves through urine and fecal matter (Agency
for Toxic Substances and Disease Registry 1999). Most
cases of elemental mercury vapor inhalation happens in
industrial settings, such as when workers are exposed to
high levels of mercury vapors or when mercury is
accidentally spilled and vaporized in warm, poor-ventilated,
or confined areas (U.S. Environmental Protection Agency
2000). On the other hand, it has been reported that oral
exposure to mercury can lead to shock, cardiovascular
collapse, renal failure, and gastrointestinal damage
(Gleason et al. 1957).
The most notable target of chronic exposure to
elemental mercury is the central nervous system. Chronic
exposure to elemental mercury elicits neurological and
psychological symptoms such as neurological degradation,
erethism (increased excitability), irritability, excessive
shyness, and tremors—symptoms only intensify and may
become irreversible as the duration of exposure and
concentration increases (Agency for Toxic Substances and
Disease Registry, 1999; United States Environmental
Protection Agency, 2000; Park and Zheng, 2012).
1.4. STUDIES OF KODAI LAKE POLLUTION
Kodai Lake, once a beautiful and pristine lake is now
home to the cascade of human waste, rags, plastics and
other debris, due to anthropogenic influences (Ramnath
2015). In addition, Kodai Lake remains to be one of many
areas in Kodaikanal polluted by the 2001 mercury spill.
Previous hydrological studies done on Kodai Lake provided
insight of the level of mercury pollution present in the
water. Initial assessment done by URS Dames and Moore
reported HgT (total mercury concentration includes
inorganic and organic forms of the metal) concentration in
the water column of less than 0.3 µg l-1 (U.R.S. Dames and
Moore 2002, Karunasagar et al. 2006). However,
Karunasagar et al. (2006) determined that the
concentration increased between 10-30% from 2002 to
2006, as their study result showed HgT concentration of
0.356-0.465 µg l-1. Since 2006, no known studies have
been conducted to determine whether the HgT
concentration has changed.
Given that mercury is an element, it is persistent in an
environment and cannot be broken down. However
mercury’s chemical form can undergo change and transfer
to and from different ecosystems (Karunasagar et al.
2006). In addition, different biogeochemical processes may
play a role in the transfer of pollutants between
ecosystems (Kwon et al. 2015). Gymkhana Marshland is
one of the major marshlands that deliver surface water
runoff from the Shola Forrest into Kodai Lake. For this
reason, we measured the mercury in Kodai Lake using
near-sediment water column samples from the lake and
water samples from the inlets and outlets from Gymkhana
Marshland. The total mercury content (HgT) in these water
samples collected from different sites was determined by
CVR Labs Pvt. Ltd. in order to obtain information on the
extent of and the factors affecting the mercury pollution in
Kodai Lake. In addition, an update of HgT concentration in
Kodai Lake is critical to determine the risk associated with
the polluted water, and thus will provide insight on the best
course for any attempts of remediation.
2.0. MATERIALS & METHODS
2.1 SAMPLE COLLECTION & PROCESSING
Water samples were collected in October 2015 from 10
sites (Fig. 1). Similar sampling points were used from D.
Karunasagar et al. (2006). Sampling points for Gymkhana
Marshland were based on the direction of water flow
throughout the marshland. Using a rowboat, samples were
collected using an industrial Nansen bottle within 1 meter
of the sediment to avoid suspended surface contaminants.
Average temperature of sample collection points was 18.6
Cº (SD=1.4). After collection, the samples were stored in
an ice cooler, transported to the laboratory, and then
stored below 0 Cº until further processing.
US EPA Method 200.8 suggests acid preservation of the
sample at the time of sample collection, however due to
the hazards of strong acids in the lake and transportation
restriction, we did not do this. Water samples were
preserved in a cooler at 4 ºC and transported to CVR Labs
Pvt. Ltd. on the same day. Upon laboratory’s receipt, the
water samples were acidified using nitric acid (HNO3).
Following acid preservation, the samples were mixed, held
for 16 hours, and verified to have a pH of 2.
Figure 2. Comparison of HgT concentration between Karunasagar
et al. (2006) and Lin (2015). Graphs are suggestive of a slow
decrease of HgT from the water column.
Lin, H.O. Mercury Pollution A9
Table 1. Summary of water sampling parameters for the experiment. (DO2 Brand) Dissolved Oxygen Sensor Probe was used to
determine ambient water temperature and depth of each point. Portable GPS device (Garmin eTrex® 20x) was used to determine
approximate coordinates and elevation of sampling points.
Sampling Point
Temp. (ºC)
Coordinates (N, E)
Elevation (m)
Sampling Depth (m)
S1
19.7
10.23057, 77.48736
2097
2.0
S2
19.6
10.23263, 77.48935
2102
4.25
S3
19.5
10.23321, 77.48425
2095
5.5
S4
19.3
10.23744, 77.48830
2102
8.5
S5
19.2
10.23455, 77.48626
2101
7.0
S6
19.7
10.23191, 77.48203
2090
0.25
S7
17.2
10.23067, 77.48205
2090
0.25
S8
15.6
10.22836, 77.48277
2097
0.25
S9
18.3
10.23003, 77.48137
2089
0.25
S10
17.4
10.23187, 77.47883
2094
0.25
2.2. INSTRUMENTATION
2.2.1. Inductively Coupled Plasma Mass Spectrometry
Due to practical difficulties and the limitations of
chemical analysis instrumentation available, only the total
concentration of inorganic and organic mercury from Kodai
lake waters were tested. Various methods reported by Puk
and Weber (1994) allowed us to determined that
Inductively Coupled Plasma Mass Spectroscopy (ICP-MS)
was available across all chemical analysis labs nearby.
Total concentration of inorganic and organic mercury was
analyzed by CVR Labs Pvt. Ltd. Using Agilent 7500 Series
ICP-MS system following US EPA Method 200.8.
2.2.2. Quality Control of Laboratory Testing Company
US EPA Method 200.8 require CVR Labs Pvt. Ltd. to
operate a formal quality control program, thus providing our
team with an ICP-MS calibration report, method blank data
summary form for metal analysis, continuing calibration
summary form, laboratory control sample summary form,
along with each quantitation summary report and
performance records that define the quality of the data
generated for the metal analyte mercury (Hg) with CASRN
No. 7439-97-6 (Creed et al. 1994).
3.0. EXPERIMENTAL
3.1. TESTING WATER SAMPLES FOR HGT
CVR Labs Pvt. Ltd. created a linearity curve for the
ICP-MS system using standard mercury Hg concentrations
of 0.5 ppb, 1 ppb, 5 ppb, 10 ppb, 20 ppb, and 50 ppb
(Appendix 1.2). To determine the total mercury
concentration in the water samples, an aliquot of each
filtered and acid preserved water sample was needed.
Appropriate volumes of (1+1) nitric acid were added to
adjust the acid concentration of each aliquot to
approximate a 1% (v/v) nitric acid solution per section
11.1.1: EPA 200.8. Each sample was then aspirated into
the reaction chamber for collection and subsequent
analysis by ICP-MS. Each liquid sample were aspirated
using a nebulizer into the spray chamber maintained at 2
ºC. Argon gas was introduced into the spray chamber to
form an aerosol. Once the aerosol was introduced into
plasma at temperature of 7,000 Kelvin, the sample
dissociated, desolvated, and ionized. All ions were
extracted through the extraction lenses, separated by
charge to mass ratio, and subsequently analyzed by the
quadruple mass detector (Creed et al. 1994).
4.0 RESULTS & DISCUSSION
4.1 CHEMICAL AND PHYSICAL FINDINGS
Water chemistry for both Kodai Lake and Gymkhana
Marshland showed an average pH value of 6 (SD=0.1). In
addition, mean dissolved oxygen content (DO2) in Kodai
Lake was lower (DO2=2.88 mg/L, SD=2.02) compared to
Gymkhana Marshland (DO2=3.54 mg/L, SD=1.53).
4.1 ICP-MS RESULTS FOR KODAI LAKE & GYMKHANA
MARSHLAND WATER COLUMNS
The total mercury concentration values were
determined in the water columns of Kodai Lake and
Gymkhana Marshland and summarized in Tables 2 and 3,
respectively. Although no data prior to the establishment of
the factory in 1983 have been reported, latest values
reported by Karunasagar et al. (2006) with CV-AAS will
serve as our baseline. Values determined by ICP-MS were
compared against this baseline in regards to the increase
or decrease of the total mercury levels due to the industrial
discharge of elemental mercury in Kodai Lake.
As seen from Table 2, Kodai Lake’s water column
showed HgT concentrations ranging from 0.17 - 0.54 µg l-1
(mean= 0.33 µg l-1, SD=0.15), while the values reported in
2006 ranged from 0.35 - 0.47 µg l-1. In addition, Table 3
summarizes HgT results for Gymkhana Marshland’s water
column with concentrations ranging from 0.16 - 1.20 µg l-1
(mean=0.65 µg l-1, SD=0.44). 95% confidence intervals for
average HgT are 0.14 – 0.52 µg l-1 for Kodai Lake and 0.09
–1.21 µg l-1 for Gymkhana Marshland (Appendix 1.1).
A closer look at Table 3 reveals remarkable
observations. Total mercury concentrations (HgT) from
ICP-MS testing revealed Gymkhana Marshland’s possible
role in the filtration of contaminants before surface water
enters into Kodai Lake. HgT values of samples from the
marshland inlets (S9 and S10, Fig.1) were higher in
comparison to HgT values of samples from the outlet (S6,
Fig.1).
BIOLOGY IN SOUTH INDIA, FALL 2015, A1-A5 A10
Table 2. Summary of ICP-MS direct analysis results from Agilent
7500 Series ICP-MS system for total mercury concentration found
in water samples from points 1-5 in Kodai Lake, following APHA
22nd EDI: 2012, 200.8. Measurements are in µg/L or µg l-1
(micrograms of organic and inorganic mercury per liter water
sample or parts per billion inorganic and organic mercury per liter
water sample).
Sampling Point
Result (µg/L)
S1
0.17
S2
0.40
S3
0.30
S4
0.23
S5
0.54
Mean=0.33 µg l-1, SD±0.15, SE=0.07
4.2. UNDERSTANDING HGT FOR KODAI LAKE &
GYMKHANA MARSHLAND
ICP-MS results obtained for samples in Kodai Lake
and Gymkhana Marshland show decreasing
concentrations of total mercury (HgT) in comparison to
concentrations reported by Karunasagar et al. in 2006.
Gilmour and Henry (1991) reported that freshwater bodies
without contamination from anthropogenic mercury
emissions generally contain less than 0.005 micrograms
per liter (µg/L) of mercury. Safe drinking water generally is
assumed to contain less than 0.025 µg/L or ppb of mercury
(Clarkson et al. 1984). In consideration to previous
freshwater studies, HgT concentrations obtained from ICP-
MS testing are well above the normal limits.
A closer comparison of HgT concentrations from our
study against Karunasagar et al. (2006) for Kodai Lake
waters presented to be unusual. HgT concentrations in the
water column from our results were slightly lower than
those from Karunasagar et al. (2006). This suggested
positive trend is supported by evidence suggesting that
different biogeochemical processes may play a role in the
transfer of pollutants from terrestrial forests into aquatic
ecosystems. Watershed runoff has been reported to be the
primary biogeochemical transfer pathway of mercury
between lake and forest ecosystems (Kwon et al. 2015).
Kodaikanal receives on average 162.56 cm of rainfall
annually (World Meteorological Organization 2016). In
addition, Kodai Lake is located at lower elevation and
therefore acts like a basin to all the surface water run off.
Although there are no watersheds directly linking the site of
the thermometer factory, we considered the possibility of
mercury deposited in soil around the site of the factory to
be washed off and delivered into Kodai Lake through rain
water, thus resulting in an increasing HgT concentrations.
On the other hand, total mercury concentrations
obtained ICP-MS testing revealed Gymkhana Marshland’s
possible role in the filtration of contaminants before surface
water enters into Kodai Lake. Given that surface watershed
run off may be the major transfer pathway of deposited
mercury in soil into Kodai Lake, our results indicate that the
disappearance of the marshland may lead to an in increase
in HgT concentrations in Kodai Lake. As mentioned above,
HgT values of samples from the marshland inlets (S9 and
S10, Fig.1) were higher in comparison to HgT values of
samples from the outlet (S6, Fig.1), thus suggests that the
marshland may be filtering surface water run off before it
enters Kodai Lake.
4.3 BIOGEOCHEMICAL PROCESSES
Bio-methylation is the process where the inorganic
form of mercury is converted to its organic form, methyl
mercury (or methyl-organo-alkyl mercury). This conversion
process is anaerobic and occurs in bottom sediments and
water columns of fresh water bodies (Gilmour et al. 2011,
Hu et al. 2013). It was reported by Karunasagar et al.
(2006) that the highest methyl mercury concentration found
in Kodai Lake waters was 0.05 µg/L.
Organic mercury or Methyl (organo) alkyl mercury
compounds are the most poisonous type of mercury.
Inorganic mercury discharge from anthropogenic sources
slowly makes its way to a nearby lake to be deposited in
bottom sediments, later undergo a chemical transformation
from inorganic to organic mercury or methyl mercury
(Agency for Toxic Substances and Disease Registry 1999).
It has been reported that such transformation process
occurs in anoxic bottom sediments and is mainly
associated with two sulfate reducing bacteria (SRB),
namely Desulfovibrio desulfuricans ND132 and Geobacter
sulfurreducens PCA (Gilmour et al. 1992, Gilmour et al.
2011, Hu et al. 2013, Kwon et al. 2015, Li et al. 2015a).
In consideration of the lower HgT concentrations we found
in Kodai Lake waters, it is possible that methylation has
been occurring since 2006 and thus may explain lower HgT
concentrations found in Kodai Lake waters with mercury
compounds now trapped in sediments. Due to practical
limitations and limited availability of high-sensitivity
instrumentation, we were not unable to test for methyl
mercury or the sediments.
Table 3. Summary of ICP-MS direct analysis results from Agilent
7500 Series ICP-MS system for total mercury concentration found
in water samples from points 6-10 in Gymkhana Marshland,
following APHA 22nd EDI: 2012, 200.8. Measurements are in µg/L
or µg l-1 (micrograms of organic and inorganic mercury per liter
water sample or parts per billion inorganic and organic
mercury per liter water sample) .
Sampling Point
Result (µg/L)
S6
0.16
S7
0.29
S8
0.95
S9
0.67
S10
1.20
Mean=0.65 µg l-1, SD±0.44, SE=0.20
4.4. REQUISITION FOR FURTHER TESTING
For a small town such as Kodaikanal, detection and
quantification of chemical species from a sample poses to
be biggest challenges in research, especially when it
comes to environmental monitoring. Methodologies for the
detection and quantification of contaminants has to be
easy to conduct, fast, and inexpensive. The study
conducted by Karunasagar et al. (2006) aimed to
determine HgT and MeHg concentrations through the use
of chemo-analytical methods, such as ultrasound
Lin, H.O. Mercury Pollution A11
extraction and the highly sensitive Cold Vapor Atomic
Absorption Spectrometry (CV-AAS). However, these
methods are expensive and impractical to local
organizations seeking to conduct environmental studies.
Other widely used techniques for this purpose includes
Mass Spectrometry (MS), inductively coupled plasma
atomic emission spectrometry (ICP-AES), high-
performance liquid chromatography (HPLC), and
electrochemistry (El Kaoutit et al. 2013). Although these
methods are more accessible in comparison to CV-AAS,
they remain impractical to Kodaikanal in consideration to
the complexities of the associated testing processes. A
chemo-analytical method by El Kaoutit et al. (2013) shows
quantification of Hg(II) in aqueous media through the use
of a colometric sensory polymer membrane and a
conventional smart phone. This method showed to be
highly sensitive and accessible in comparison to
conventional method for mercury testing. In addition, other
quantification studies utilizing similar methods have
reported successful experience while using colometric
sensory polymer membranes (Jana et al. 2009, Chaudhary
et al. 2015).
Further studies are required to fully understand the
effects of the mercury pollution in the town of Kodaikanal.
Studies must be conducted frequency to determine and
monitor mercury concentrations (both organic and
inorganic) in aquatic organisms, sediment column, and
water originating from Kodai Lake. In addition, Kodai Lake
waters are stored by the Palni Hills water reservoir,
providing water to thousands of homes. For this reason,
health surveys must be conducted to determine whether
the people consuming water originating from Kodai Lake
exhibits signs or symptoms of mercury poisoning.
5.0. ACKNOWLEDGEMENTS
We would like to thank Dr. Anne Walter, Dr. Michael
Swift, and Dr. Sara Fruehling for advising our projects
during the Biology in South India Research Program. We
also would like to thank Mr. Madhu Ramnath, Mrs. Pippa
Mukherjee, and the entire staff at the Palni Hills
Conservation Council for welcoming and advising us, as
well as extending the use of their facilities to our team
during the course of the project.
6.0 REFERENCES
Agency for Toxic Substances and Disease Registry. 1999. Toxicological
Profile for Mercury.in P. H. S. U.S. Department of Health and Human
Services, editor., Atlanta, GA.
Baum, C. R. 2012. Mercury: What's In It For Kids? Clinical Pediatric
Emergency Medicine 13:324-330.
Census Organization of India. 2011. Kodaikanal Population Census
2011.in C. Chandramouli, editor.
Chaudhary, J. P., A. Kumar, P. Paul, and R. Meena. 2015.
Carboxymethylagarose-AuNPs generated through green route for
selective detection of Hg2+ in aqueous medium with a blue shift.
Carbohydrate Polymers 117:537-542.
Clarkson, T., J. Cranmer, D. Sivulka, and R. Smith. 1984. Mercury Health
Effects Update: Health Issue Assessment.in U. S. E. P. Agency,
editor., Washington, D.C.
Clarkson, T. W. 1993. Mercury: major issues in environmental health.
Environmental Health Perspectives 100:31-38.
Creed, J. T., C. A. Brockhoff, and T. D. Martin. 1994. Method 200.8:
Determination of Trace Elements in Waters and Wastes by
Inductively Coupled Plasma - Mass Spectrometry (EMMC Version,
5.4).in O. o. R. a. D. Environmental Monitoring Systems Laboratory,
editor., Cincinnati, Ohio 45268.
El Kaoutit, H., P. Estevez, F. C. Garcia, F. Serna, and J. M. Garcia. 2013.
Sub-ppm quantification of Hg(ii) in aqueous media using both the
naked eye and digital information from pictures of a colorimetric
sensory polymer membrane taken with the digital camera of a
conventional mobile phone. Analytical Methods 5:54-58.
Gilmour, C. C., D. A. Elias, A. M. Kucken, S. D. Brown, A. V. Palumbo, C.
W. Schadt, and J. D. Wall. 2011. Sulfate-Reducing Bacterium
Desulfovibrio desulfuricans ND132 as a Model for Understanding
Bacterial Mercury Methylation. Applied and Environmental
Microbiology 77:3938-3951.
Gilmour, C. C., and E. A. Henry. 1991. Mercury methylation in aquatic
systems affected by acid deposition. Environmental Pollution 71:131-
169.
Gilmour, C. C., E. A. Henry, and R. Mitchell. 1992. Sulfate stimulation of
mercury methylation in freshwater sediments. Environmental
Science and Technology 26:2281-2287.
Gleason, M., R. Gosselin, and H. Hodge. 1957. Clinical toxicology of
commercial products. Williams and Wilkins Co., Baltimore, MD.
Gochfeld, M. 2003. Cases of mercury exposure, bioavailability, and
absorption. Ecotoxicology and Environmental Safety 56:174-179.
Greenpeace. 2001. Dangerous Mercury Thermometer Factory and Waste
Dump in India Has Links to Major U.S. Company.
Hu, H., H. Lin, W. Zheng, S. J. Tomanicek, A. Johs, X. Feng, D. A. Elias,
L. Liang, and B. Gu. 2013. Oxidation and methylation of dissolved
elemental mercury by anaerobic bacteria. Nature Geosci 6:751-754.
Jana, A., J. S. Kim, H. S. Jung, and P. K. Bharadwaj. 2009. A cryptand
based chemodosimetric probe for naked-eye detection of mercury(II)
ion in aqueous medium and its application in live cell imaging.
Chemical communications (Cambridge, England):4417-4419.
Justice Bhargava, S. 2003. Report On The Alleged Environmental
Pollution And Health Impacts Caused By The Hindustan Lever
Mercury Thermometer Factory At Kodaikanal. Indian People
Tribunal.
Karunasagar, D., M. V. Balarama Krishna, Y. Anjaneyulu, and J.
Arunachalam. 2006. Studies of mercury pollution in a lake due to a
thermometer factory situated in a tourist resort: Kodaikkanal, India.
Environmental Pollution 143:153-158.
Kodai.com. 2016. Kodaikanal Boat Club.
Kwon, S. Y., J. D. Bluma, K. J. Nadelhoffer, J. T. Dvonch, and M. T.-K.
Tsui. 2015. Isotopic study of mercury sources and transfer between
a freshwater lake and adjacent forest food web. Science of the Total
Environment 532:220-229.
Li, C., Q. Zhang, S. Kang, Y. Liu, J. Huang, X. Liu, J. Guo, K. Wang, and
Z. Cong. 2015a. Distribution and enrichment of mercury in Tibetan
lake waters and their relations with the natural environment.
Environmental Science and Pollution Research 22:12490-12500.
Li, J., Q. Zhou, G. Yuan, X. He, and P. Xie. 2015b. Mercury
bioaccumulation in the food web of Three Gorges Reservoir (China):
Tempo-spatial patterns and effect of reservoir management. Science
of the Total Environment 527:203-210.
Lockwood, I. 2003. On the danger list. india's National Magazine.
Frontline.
Park, J., and W. Zheng. 2012. Human Exposure and Health Effects of
Inorganic and Elemental Mercury. Journal of Preventive Medicine
and Public Health 45:344-352.
PhysLink.com, A. S. 2016. Where is mercury found in the world?
U.R.S. Dames and Moore. 2002. Environmental Site Assessment and
Prelimi-nary Risk Assessment for Mercury, Kodaikkanal
Thermometer Factory, Tamil Nadu. Prepared for Hindustan Lever
Limited (HLL).
U.S. Environmental Protection Agency. 2000. Mercury Compounds:
Hazard Summary.
World Meteorological Organization. 2016. Climatological Information for
Kodaikanal, Tamil Nadu, India.
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